1. Field of Invention
The present invention relates to log feeders in general and in particular a method and apparatus for singulating logs with a step log feeder having reduced starting power requirements and improve feed speeds.
2. Description of Related Art
In the field of lumber production logs are frequently introduced into a sawmill in a grouping which must first be separated from each other to feed into a conveyor belt entering the mill. One common apparatus for accomplishing this separation or singulating as it is referred to in the art is a step feeder. As illustrated in FIG. 1, a step feeder 10 commonly includes two moving members connected by a common driven linkage having inclined steps that feed logs up to a fixed incline surface at the top such that the reciprocating movement of one of the moving members advances each log up the inclined slope of the step feeder one inclined step at a time and over the fixed incline surface at the exit of the step feeder.
A common difficulty with conventional step feeders occurs when an operator pauses the step feeder to permit a preceding log to be advanced out of the way of the exit to the step feeder. With conventional step feeders, as the log will be dropped onto an awaiting conveyor belt at the topmost position of the moving member, the operator is required to stop the step feeder part way through the lifting portion of the reciprocating motion of the step feeder with the moving member part way up the incline plate surface at the exit of the step feeder so as to prevent the log from being inadvertently discharged from the step feeder. Such positioning of the log therefore requires that in order to restart the step feeder, the log must be lifted from a resting position while the step feeder comes up to operating speed. As this is part way through the lifting portion of the lift and retract reciprocating motion of the step feeder, more power is required to start from this position and it takes more time to complete the cycle to feed the log and go back to the bottom to retrieve another log.